The long-term goal is to demonstrate that the Anti-Polymer Antibody Assay is diagnostic for chronic fatigue syndrome patients and fibromyalgia patients. In a pilot study 55 % (6/11) of chronic fatigue syndrome patient sera, 71 % (12/17) of fibromyalgia patient sera and 9 % (1/11) sera from healthy normals were seroreactive on the Anti-Polymer Antibody Assay. Therefore, it is hypothesized that the Anti-Polymer Antibody Assay is diagnostic for chronic fatigue syndrome patients and fibromyalgia patients. The purpose of this proposal is to establish the ability of the assay to identify chronic fatigue patient sera and fibromyalgia patient sera in a retrospective multi-center blinded trial. The data generated from the multi-center trial will be used as the basis for the submission of a prospective Phase II multicenter trial. In addition, data from the Phase I trial will be used in the application to the Food and Drug Administration for approval of the Anti-Polymer Antibody Assay as a diagnostic test for chronic fatigue syndrome and fibromyalgia. PROPOSED COMMERCIAL APPLICATION: The research will demonstrate that the APA Assay is diagnostic for chronic fatigue syndrome and fibromyalgia. These syndromes afflict approximately 2-5 % of the adult population in industrialized nations.